I start emacs from a xterminal and try to close it from file->exit emacs the whole x system crashes, the mouse and the keyboard doesn't work. I have to kill the X system loging in from another machine, and kill the x system. If I close emacs form the x button on the frame of the window everything works fine.
This is probably a problem with the font server - make sure you update to the latest errata X RPMs.